For example, it is promising to use environmental power generation in which a power line and a signal line that poses problems in construction of a sensor network are unnecessary. As the environmental power generation, power generation using a thermoelectric conversion element that generates electricity due to a temperature difference is effective in addition to solar power generation.
For example, there is a technology that causes a temperature difference in a thermoelectric conversion element by using a change over time in the temperature of a heat source. In this case, the heat source is brought into contact with one side of the thermoelectric conversion element, and a heat storage material is brought into contact with the other side. In addition, as the temperature of the heat source changes over time, a temperature difference is generated between the heat source and the heat storage material, and the thermoelectric conversion element generates electricity in accordance with the temperature difference.
In addition, for example, there is a technology that uses two or more heat storage materials having different operating temperatures to increase the amount of power generation.
When two or more heat storage materials having different operating temperatures are used to increase the amount of power generation, it is conceivable to place the two or more heat storage materials in different containers such that heat is transferred to the heat storage materials through the respective containers.
The followings are reference documents.
[Document 1] International Publication Pamphlet No. WO2012/133790 and
[Document 2] International Publication Pamphlet No. WO2013/099943